| | """ Standard "encodings" Package |
| | |
| | Standard Python encoding modules are stored in this package |
| | directory. |
| | |
| | Codec modules must have names corresponding to normalized encoding |
| | names as defined in the normalize_encoding() function below, e.g. |
| | 'utf-8' must be implemented by the module 'utf_8.py'. |
| | |
| | Each codec module must export the following interface: |
| | |
| | * getregentry() -> codecs.CodecInfo object |
| | The getregentry() API must return a CodecInfo object with encoder, decoder, |
| | incrementalencoder, incrementaldecoder, streamwriter and streamreader |
| | attributes which adhere to the Python Codec Interface Standard. |
| | |
| | In addition, a module may optionally also define the following |
| | APIs which are then used by the package's codec search function: |
| | |
| | * getaliases() -> sequence of encoding name strings to use as aliases |
| | |
| | Alias names returned by getaliases() must be normalized encoding |
| | names as defined by normalize_encoding(). |
| | |
| | Written by Marc-Andre Lemburg (mal@lemburg.com). |
| | |
| | (c) Copyright CNRI, All Rights Reserved. NO WARRANTY. |
| | |
| | """ |
| |
|
| | import codecs |
| | import sys |
| | from . import aliases |
| |
|
| | _cache = {} |
| | _unknown = '--unknown--' |
| | _import_tail = ['*'] |
| | _aliases = aliases.aliases |
| |
|
| | class CodecRegistryError(LookupError, SystemError): |
| | pass |
| |
|
| | def normalize_encoding(encoding): |
| |
|
| | """ Normalize an encoding name. |
| | |
| | Normalization works as follows: all non-alphanumeric |
| | characters except the dot used for Python package names are |
| | collapsed and replaced with a single underscore, e.g. ' -;#' |
| | becomes '_'. Leading and trailing underscores are removed. |
| | |
| | Note that encoding names should be ASCII only. |
| | |
| | """ |
| | if isinstance(encoding, bytes): |
| | encoding = str(encoding, "ascii") |
| |
|
| | chars = [] |
| | punct = False |
| | for c in encoding: |
| | if c.isalnum() or c == '.': |
| | if punct and chars: |
| | chars.append('_') |
| | if c.isascii(): |
| | chars.append(c) |
| | punct = False |
| | else: |
| | punct = True |
| | return ''.join(chars) |
| |
|
| | def search_function(encoding): |
| |
|
| | |
| | entry = _cache.get(encoding, _unknown) |
| | if entry is not _unknown: |
| | return entry |
| |
|
| | |
| | |
| | |
| | |
| | |
| | |
| | |
| | norm_encoding = normalize_encoding(encoding) |
| | aliased_encoding = _aliases.get(norm_encoding) or \ |
| | _aliases.get(norm_encoding.replace('.', '_')) |
| | if aliased_encoding is not None: |
| | modnames = [aliased_encoding, |
| | norm_encoding] |
| | else: |
| | modnames = [norm_encoding] |
| | for modname in modnames: |
| | if not modname or '.' in modname: |
| | continue |
| | try: |
| | |
| | |
| | mod = __import__('encodings.' + modname, fromlist=_import_tail, |
| | level=0) |
| | except ImportError: |
| | |
| | |
| | pass |
| | else: |
| | break |
| | else: |
| | mod = None |
| |
|
| | try: |
| | getregentry = mod.getregentry |
| | except AttributeError: |
| | |
| | mod = None |
| |
|
| | if mod is None: |
| | |
| | _cache[encoding] = None |
| | return None |
| |
|
| | |
| | entry = getregentry() |
| | if not isinstance(entry, codecs.CodecInfo): |
| | if not 4 <= len(entry) <= 7: |
| | raise CodecRegistryError('module "%s" (%s) failed to register' |
| | % (mod.__name__, mod.__file__)) |
| | if not callable(entry[0]) or not callable(entry[1]) or \ |
| | (entry[2] is not None and not callable(entry[2])) or \ |
| | (entry[3] is not None and not callable(entry[3])) or \ |
| | (len(entry) > 4 and entry[4] is not None and not callable(entry[4])) or \ |
| | (len(entry) > 5 and entry[5] is not None and not callable(entry[5])): |
| | raise CodecRegistryError('incompatible codecs in module "%s" (%s)' |
| | % (mod.__name__, mod.__file__)) |
| | if len(entry)<7 or entry[6] is None: |
| | entry += (None,)*(6-len(entry)) + (mod.__name__.split(".", 1)[1],) |
| | entry = codecs.CodecInfo(*entry) |
| |
|
| | |
| | _cache[encoding] = entry |
| |
|
| | |
| | |
| | try: |
| | codecaliases = mod.getaliases() |
| | except AttributeError: |
| | pass |
| | else: |
| | for alias in codecaliases: |
| | if alias not in _aliases: |
| | _aliases[alias] = modname |
| |
|
| | |
| | return entry |
| |
|
| | |
| | codecs.register(search_function) |
| |
|
| | if sys.platform == 'win32': |
| | def _alias_mbcs(encoding): |
| | try: |
| | import _winapi |
| | ansi_code_page = "cp%s" % _winapi.GetACP() |
| | if encoding == ansi_code_page: |
| | import encodings.mbcs |
| | return encodings.mbcs.getregentry() |
| | except ImportError: |
| | |
| | pass |
| |
|
| | codecs.register(_alias_mbcs) |
| |
|